InGaN light-emitting diodes with indium-tin-oxide photonic crystal current-spreading layer

– KH Li, and HW Choi

FE-SEM images showing (a) ordered hexagonal monolayer arrays of nanospheres on a GaN LED wafer, (b) the nanosphere-coated sample after ICP etching, and (c) a close-up view of the ITO nano-pillars and the resultant nano-pillar arrays with diameters of (d) 500, (e) 700, and (f) 1000 nm.

Journal of Applied Physics, vol. 110, 5, pp. 053104 (2011)

Photonic crystal patterns on the indium tin oxide layer of an InGaN/GaN light-emitting diode are fabricated via nanosphere lithography in combination with dry etching. The silica spheres acting as an etch mask are self-assembled into a hexagonal closed-packed monolayer array. After etching, the photonic crystal (PhC) pattern is formed across the indium-tin-oxide (ITO) films so that the semiconductor layers are left intact and thus free of etch damages. Despite slight degradation to the electrical properties, the ITO-PhC light-emitting diodes (LEDs) exhibit enhancements of their optical emission power by as much as 64% over an as-grown LED. The optical performances and mechanisms of the photonic crystal LEDs are investigated with the aid of rigorous coupled wave analysis and finite-difference time-domain simulations.

DOI: 10.1063/1.3631797